The present invention relates to devices for conveying microwave frequency energy between coaxial and microstripline transmission media, and more particularly to orthogonal coaxial-to-microstripline launchers.
In some applications, such as active array antennas and communication satellite systems, it is desirable to integrate coaxial lines to the microstripline medium, typically between microwave integrated circuit (MIC) packages. Such interfaces have in the past been made by right angle coaxial connectors or direct coaxial-to-microstripline right angle junctions. Right angle coaxial connectors are not well matched at X-band frequencies (VSWR greater than 1.25:1), and can be attached only along the sides of the MIC packages.
The direct coaxial-to-microstripline right angle junction is characterized by narrow band performance, and the attachment to the MIC package is potentially blind if routed through the top cover of the package. Moreover, higher order modes can radiate when the connection is routed through the air space of the microstripline. The mechanical assembly of a direct right angle junction is typically difficult and, further, it is difficult to rework the junction or perform RF tuning after the assembly is made.
It is therefore an object of the present invention to provide a compact microstrip feed network, permitting an extra degree of freedom in being able to locate the RF interfaces along the top and bottom faces of a MIC package as well as its sides.